Hi R., I had it really bad too with my son..same deal, couldn't walk, (or walked like a grandma!), my leg gave out randomly, etc. For temporary relief, try down dog yoga pose with toes turned inward and hold for as long as you can. I ended up seeing a chiropractor which helped a lot. My sciatica was actually a result of SI joint inflammation (where the hip bone connects to the back bone) which put my pelvis out of alignment and pressed on a swollen sciatic nerve. I was told this is pretty common in pregnancies, esp. 2nd, 3d, 4th, etc. (my son was my 2nd). Once the SI joint was realigned by the chiro, it took the pressure off the sciatic and the pain substantially subsided (although didn't completely go away until I had my son). So that's the best advice i can offer. Some other things that helped- try sitting and rolling your hips around on a big yoga/pilates ball (I used one for my desk chair at the office) and also swimming a couple nights a week (or as much as possible) to take the weight off your feet/hips. Also try to get a good massage if you can swing it. Good luck- i know it's SO painful, mine started at about 30 weeks and it was sometimes too much to bear. But the chiro really helped, as did all of these other stop-gap measures until Tyson was born.